Motion Control Of An Omnidirectional Robot With Five Degrees Of Freedom

This thesis mainly studies the mobile robots with omnidirectional features. The specific research content includes the different methods to obtain the omnidirectional features, the affects to the movement by the different structures of the omnidirectional chassis, the movement characteristics and the control approach corresponding to specific chassis.First, the concept of omnidirectional theory is introduced and the approach to obtain the omnidirectional features is illustrated. For the planar mobile robot, there are two methods to obtain the omnidirectional carrier, which include add-DOF method and retain-convert-DOF method. According to this theory, the design standards of MY series are summarized and the implementation of movement transformation is verified. The movement transformation of omnidirectional wheels in longitudinal assemblies is incomplete, so the double spherical crowns differential omnidirectional wheels(DSCDOW) is designed to solve this problem.Then, the movement property of omnidirectional robot is studied. The kinematics model of the chassis in different structures are established and the advantages and disadvantages of different models are illustrated. By simulation, it is observed that the trajectory following error of lateral model is smaller. And then the velocity anisotropy and isosyntropy are analyzed. The rotation compression theory is proposed and a further interpretation is made by conducting the trajectory planning of a circle. The simulation shows that it is necessary to choose the right solution according to the radius of the circle. The study about the movement property makes a preparation to planning more complex trajectory.Last, the control system of 5DOF-OMR is introduced, including the overall structure of the control system and the constitution of each submodule. A PD controller using hydroponic tangent is proposed to following the reference trajectory. The simulation results shows that the stabilization and compression function of the controller are verified and the controller can reduce the slippage caused by oversize-acceleration. The field experiment shows the influence of the environment and the internal problem robot itself to the results. Several improvement measures are addressed to the further work. Finally, the assembly experiment is conducted.